1. Field of the Invention
The present invention is related to a noise cancellation device for an image signal processing system, and more particularly, to a noise cancellation device capable of performing filtering operations for image signals according to a motion degree of images, so as to reduce noise, improve image quality, and maintain definition of the images.
2. Description of the Prior Art
With rapid developments of communication and computer techniques, image applications have more and more variety. Briefly, each of the image applications can be regarded as a combination of an image data source and a player. The image data source can be any device capable of outputting image signals, such as a computer, a DVD player, a cable or wireless television signal LS (Launch-Station), a video game player, etc., and is utilized for outputting image signals to the player through wired or wireless channels, so as to display images. During signal transmission, signals are inevitably interfered by noise, topography, and surface features. Even in the image data source or the player, signals processed by the image data source or the player may be mingled with unanalyzable elements of noise due to circuit defects or environment conditions (e.g. temperature or humidity), which reduces image quality.